Visit a doctor’s office for almost anything that ails you and the chances are good you will have your blood pressure measured. That’s because it is an essential diagnostic procedure to detect hypertension, a common condition that puts people at risk of heart and kidney disease.

Considering that millions of people have their blood pressure checked every day, it is surprising that this measurement can be so tricky. Mistakes are far more common than most people realize, and the consequences of inaccuracies can be serious.

Falsely Positive Blood Pressure Readings:

A false positive, that is, a reading higher than the true blood pressure, could lead to unnecessary medication. Drugs can be expensive and may have unpleasant side effects such as dizziness, fatigue, impotence, cough or swollen feet.

Falsely Negative Blood Pressure Readings:

A false negative, a reading lower than the actual blood pressure, could lead to undertreatment. This puts people at risk of heart attacks, strokes or kidney disease.

Blood Pressure Cuff:

What causes such errors? According to experts writing in the Journal of Human Hypertension (July, 1997), a common source of error in measuring blood pressure is using the wrong size cuff. A cuff that is too small for a large arm can result in a blood pressure reading higher than it should be. When was the last time a nurse or doctor actually measured your arm circumference and then selected a blood pressure cuff that was designed for your sized arm? Most of the time you will be measured with the device that is handy.

Too Much Talking Going On:

Another potential problem is talking. Not infrequently a nurse or physician taking blood pressure will strike up a conversation, thinking that it may put the patient at ease. On the contrary, talking during blood pressure measurement can easily raise the reading 10 to 20 points.

When we first heard about this phenomenon we were skeptical. How could seemingly casual conversation affect blood pressure? Research by J.J. Lynch, however, has revealed that when someone talks while having her blood pressure measured can have a profound impact on the outcome. In some cases blood pressure can go far higher than 20 points and could result in a false diagnosis of hypertension.

Arm Position Is Important:

The official position of the American Heart Association is that the “Patient’s arm should be supported at heart level.” If your arm is allowed to hang down lower than heart level the reading is likely to be falsely elevated. If, for some odd reason, your arm is allowed to rest above heart level the reading could be falsely lowered.

You might think this fundamental recommendation from the AHA would always be followed. You would be wrong. It never fails to amaze us that most chairs in exam rooms do not have an arm rest at heart level. Unless the nurse or doctor actually supports your arm at the correct level while measuring your blood pressure, chances are good that your arm will be lower than appropriate and that will falsely elevate the reading.

Another problem that is rarely considered by health professionals is a cold examining room. If you are wearing one of those flimsy little paper gowns, feeling chilly and exposed may increase blood pressure more than 10 points.

White Coat Hypertension:

And speaking of uneasiness, “white coat hypertension” affects up to one patient in five. These are people whose blood pressure skyrockets when the doctor walks into the room. Some people with normal blood pressure may have office readings as high as 180/110.

Many doctors and nurses have a hard time accepting this concept. After all, how could their mere presence cause a patient’s blood pressure to spike? Health professionals like to think of themselves as kind, compassionate healers, not scary threats to a patient’s well being. Nevertheless, many people become very anxious the minute a doctor knocks on the exam room door.

Anyone who is susceptible to this phenomenon should be measuring blood pressure at home. There are affordable, easy-to-use digital machines that allow people to keep a diary of their readings over the course of several weeks or months. This permits the physician to get a broader understanding of their blood pressure in a variety of settings. The home machine should always be checked against the equipment in the doctor’s office to make sure it is accurate.

Anyone who would like additional details about proper blood pressure measurement, white coat hypertension and drugs used to treat high blood pressure may find our Guide to Blood Pressure helpful. It has a detailed list of dos and don’ts of measuring and managing blood pressure.

Measuring blood pressure is harder than it looks. Getting it right requires good technique and careful monitoring over time. This facilitates the best possible treatment for those who need it and protects others from unnecessary medication.

Share your own experience with blood pressure measurement below and please vote on this article at the top of the page.

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57 Thoughts Shared

Mark

Sydney - Australia

November 2, 2016 at 7:44 pm

1) I visited my local pharmacy and they suggested a blood pressure test using their OMRON BPM. It was high (around 140/90). They send me to my Dr.

2) My Dr, using his own OMRON BPM, found my BP high… He gave me 1 pill (Coversyl).

3) Months later my Dr gave me a second pill (Zanidip – I think).

4) Months later my Dr gave me a third pill (Minipress).

5) I bought my own OMRON … measured High (~ 140 / 90) STILL after all those pills!!!!

6) I bout a second OMRON … for the office… still measure HIGH.

Numerous side effects ….

Along the way I stop one of the pills on my own will. NO CHANGE

I requested to my Dr to be sent to a BP specialist. After 3 visits and numerous tests using MANUAL BPM and other computerised equipment + ECG, etc etc etc… over the 3 visits my BP was even below normal (~ 117/78) – measured numerous times over 3 visits.

I have now stopped a second pill. Feel much better … less side effects….

I will soon stop the 3rd and final pill.

I reckon these FREE machines given to pharmacies in Australia, Free to Doctors and Free to Surgeries are a real scam… forcing Drs to prescribe pills and creating huge side effects (obviously that more pills will cure). Good Lord!!!!

D.B.

June 16, 2016 at 9:16 pm

Just after I entered menopause, my doc felt I had high blood pressure – even though readings were taken as many have described above. (I was having lots of trouble sleeping at the time.) She put me on HCTZ. After a couple of days, I was feeling really awful. Dizzy, nauseated, shaky, no energy. After 4 days, my heart was racing – 120 beats/minute – and I was just relaxing in a recliner reading the newspaper.

I called to report the side effects and was told by the nurse that these side effects were not listed under this medication. I let her know that they were listed in the info I got from the pharmacy. After talking with the doctor, the nurse said they’d switch me to a Beta Blocker, until I reminded her that I have asthma – so a Beta Blocker would not be a good idea for me! I think my electrolytes were completely out of balance. No one ever suggested a smaller dose or anything else.

I recently worked with a functional medicine practitioner to figure out why I couldn’t lose weight and was still very fatigued. Since January I have lost about 25 pounds of fat and have healed my esophagus of Barrett’s and healed SIBO and have lots less inflammation, and guess what! My blood pressure is much better. Funny, though, the FM practitioner never takes my blood pressure the same way twice and often does it incorrectly, too! I still take my own blood pressure at home a couple times a week, just to keep my eye on it.

Rufina

Arizona

April 17, 2016 at 11:03 am

My Omron is so inconsistent. It will start with a high reading, i.e., 133/70, and as I keep taking more readings, alternating between my two arms, the reading gets lower to about 113/70. Now that confuses me. 133 is considered hypertensive for my age, 48, but not 113. I do not use the battery-powered omron. I plug it to an outlet thinking it’ll be more consistent and accurate with stable flow of power. My arm is rested and supported at heart level when i do this. I need to take at least 6 readingd every single session just so i get a pair of readings closest to each other. I’m so frustrated with Omron now ; (

Sue

Edinburgh

July 21, 2016 at 1:07 pm

John

Central oregon

March 29, 2016 at 9:01 pm

I was diagnosed with high blood pressure. The doctor then gave me a medicine to bring it down it was making me dizzy all the time. So I got my own blood pressure machines I got two of them one on my wrist and the other on my arm.
According to the two little machines I do not have high blood pressure, and I record them on the app on my iPhone to show the doctor every time I go in.

Deepa

kochi

January 18, 2016 at 4:13 am

I just received my Omron BP monitor. My husband had a correct reading and so did my fil. I have normal BP but my reading and pulse rate declare that I should be having some heart problem. It is ridiculous especially because a normal BP test by doctor says normal. I wonder if the cuff is too large for my arm.

Marie

USA

November 5, 2015 at 8:15 am

I also agree with Gw about the doctors office. There is no support given to the arms at all and the feet are dangling from the examining table. Can I ask a question here? When someone is taking blood pressure measurement twice, which one is the correct one. Thank you for this post and God bless you, Marie

Alice

Indiana

October 8, 2015 at 3:06 pm

Most doctors and nurses don’t even know where the brachial artery on the inside of the arm is either. Most doctors and nurses don’t consider the shape of the arm. There has only been a very few times that either a doctor or nurse has taken a blood pressure measurement that were vary close to mind. I also question about how good their hearing is as well. I started taking my blood pressure about 20 years ago because I didn’t trust the doctor’s readings. I think most doctors and nurses need to take training how to take blood pressure properly.

Debbie

Houston, TX

September 9, 2015 at 5:37 pm

I had my blood pressure checked at an endocrinologist’s office. When the young woman finished I asked her what the reading was. She told me it was 124. I asked her 124 over what? Her reply was it is just 124 that is all!

I have been in many doctor’s offices that claim my bp normal, which is so far from the truth. I have a great deal of problems with my blood pressure and it hasn’t been normal in at least 20 years. Unfortunately this effects the medical care you get.

My suggestion is to keep a detailed record of your bp in a notebook and bring it in with you. It is important to show that this isn’t a new event, that this has been ongoing.

Laurel

Georgia

September 8, 2015 at 7:56 pm

I am able to donate blood regularly, and they write down the blood pressure readings for me. I take these readings with me to the doctor’s office as proof that normally my readings are acceptable. The folks at the Red Cross do take the readings with my feet on the floor, arm on a table at nearly heart level, quietly, and with a large enough cuff. I trust their readings. The waiting areas are quiet.

I do not know if they take drop-ins, but if you have one close and are concerned, it wouldn’t hurt to ask. They certainly have no vested interested in the results.

Grace

NC

September 7, 2015 at 9:26 pm

I was diagnosed with high BP 30 years ago and have been on medication ever since. A double mastectomy and removal of all lymph nodes in both arms has resulted in lymphedema in both arms — thus, I cannot have blood pressure (or blood work/infusions, etc.) done on my arms. While one person at our cancer center used to take BP near my calf, my primary care office has pretty much stopped monitoring my BP at all. No matter where I go to my — gastroenterologist, gynecologist, urologist, heart specialists, surgeons, neurologist, endocrinologist etc. — no one has ever heard of not using arms to check for BP, they either skip it altogether or several struggle together to come up with another place to put a cuff……..

LOUIS

FLORIDA

September 7, 2015 at 10:54 am

In addition to no talking, I have found that no body movement–head, arms, legs and shifting around will result in a most accurate reading, whether at home or in the doctor’s office.
differences of 10 to 40 points higher occur.

SH

NC

September 6, 2015 at 4:22 pm

My husband has HBP and has this Omron Blood Pressure monitor. Omron HEM-711AC Automatic Blood Pressure Monitor with IntelliSense. Every time he goes to the doctor his blood pressure readings are much lower than what he gets with the machine. Changing the batteries helped some, but the readings were still 15 to 20 points higher with the machine. We bought a regular Sphygmomanometer and a stethoscope and started doing it manually instead and his BP is much lower than any of the measurements the machine was taking. I highly advise anyone with a machine to take your BP manually occasionally to check the accuracy of the unit they are using. Ours was reading so high it was scary at times.

Alice

Indiana

October 8, 2015 at 4:49 pm

I stopped using digital sphygmomanometers for the reasons you mentioned. The Main Artery Pressure (MAP) and the Pulse on these digital machines work together to determine the systolic and diastolic. You will find that the pulse that the machine gives is much higher then if you take your pulse manually using your finger and a watch with a second hand, especially if you take your blood pressure in the morning. The differences between the 2 pulse readings can be as little as +/-4 to cause the systolic and diastolic to be way off. I have been using a manual sphygmomanometer ever since I found out how these digital things work and the reason they are off.

carol

September 5, 2015 at 8:56 am

I always take my BP at home for the week prior to my doctor visit and give her the readings. As a registered nurse, I am appalled by what I see when the assistants take BP’s. You are sitting on the end of the exam table with your legs dangling and your arm is hanging down. They also never seem to put the cuff on tight enough to pick up an accurate reading. My brachial pulse is difficult to palpate so the cuff needs to be snug to pick up the pulse. I have had readings of 180/110 with the cuff is not even touching my skin but when the cuff is on snug the reading comes down to 120/80. The assistants also don’t allow for a 10 minute rest period after escorting you to the exam room. I bet over half of people on drugs for hypertension have normal blood pressure,

gw

So Cal

September 4, 2015 at 11:27 pm

This blog should be required reading for every nurse and pa that takes blood pressures on a daily basis. I too, have never had my bp taking correctly at a doctor’s office. The numbers are always much higher than what I get on my home device.
Also, where is the real science/research that shows taking medication to lower bp does more good than harm? Should treatment be based on your home average or your doctor’s office first reading? It seems that millions of people are being over-prescribed meds based on faulty testing.
It is really disturbing that such a simple test is so incompetently performed almost universally by medical “professionals.” It makes me worry about whether other medical testing is performed safely and correctly.

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